Ring grinding fixture



Sept. 24, 1963 J. H. THOMPSON 3,104,504

RING GRINDING FIXTURE Filed Feb. 7, 1961 4 Sheets-Sheet 1 A TJ'ORNEYSept. 24, 1963 .1. H. THOMPSON 3,104,504

RING GRINDING FIXTURE Filed Feb. 7, 1961 4 Sheets-Sheet 2 IN VEN TOR.

%EATTORNEY Sept. 24, 1963 J. H. THOMPSON 3,104,504

RING GRINDING FIXTURE Filed Feb. 7, 1961 4 Sheets- Sheet 3 7 INVENTOR.

(Vii/2 J. $4405.41

A Y'TORNJY Sept. 24, 1 6 J. H. THOMPSON RING GRINDING FIXTURE 4Sheets-Sheet 4 Filed Feb. 7, 1961 INVENTOR. fiifi ifZo/gwm BY ATTORNEYUnited States Patent 3,104,504 EWC- GRIN DING FDITURE John H. Thompson,Grand Rapids, Mich, assignor to General Motors Corporation, Detroit,Mich, a corporation of Delaware Filed Feb. 7, 1961, Ser. No. 87,641Claims. or. 51-415 This invention relates generally to industrialfixtures and more particularly involves apparatus and amethod toindividually feed and position large numbers of piston rings forgrinding.

One of the important objectives of the invention is to provide apparatuswhich is adapted to grind the peripheries of a large number of splitpiston rings one at a time.

A further objective of the invention is to provide a unique method forachieving such individual grinding.

The advantages of such a fixture and method are several. First, a moreuniform quality ring is obtained which has zero point protrusion at ringgap. Second, any desired true cylindrical shape can be produced on thering diameter. Finally, each piece may be produced at a lower netmanufacturing cost and peripheral lines on the ring diameter may beobtained to provide more uniform seating.

The special fixture which forms the subject of this invention is adaptedto be mounted on and used in conjunction with a chucking-type grinder.

For a more detailed understanding of the invention and the objects andadvantages thereof, reference may be made to the drawings in which:

FIGURE 1 is a side view in elevation of the special fixture.

FIGURE 2 is a view in plan taken substantially on the line 2-2 of FIGURE1 showing certain parts broken away and in section to more clearlyillustrate details of the device.

FIGURE 3 is a View similar to that of FIGURE 2 except that it has beensubstantially enlarged and other portions broken away to show one of therings being received in the tapered area in front of the special carrierfor locating the ring for grinding.

FIGURE 4 is similar to FIGURE 3 except that it shows the ring beingcarried forward in the tapered area by the carrier up a ainst thegrinder face plate where it is further compressed in the tapered area soas to close the gap in the ring.

FIGURE 5 again is like FIGURES 3 and 4 except that the live center ortailstock is shown clamping the ring against the grinder face plate withthe carrier retracted so that the ring is in final position forgrinding.

FIGURE 6 shows certain details of the magazine or loading bar on whichthe rings are placed prior to being fed one at a time for grinding.

FIGURE 7 illustrates further details of the magazine including how therings are retained thereon and biased into the loader attachment.

FIGURE 8 is a View taken substantially on the line S% of FIGURE 7 withparts broken away and in section illustrating how the magazine ismounted and also the operation of the keys or tabs which retain therings on the magazine.

FIGURE 9 is a view in elevation taken substantially on the line 9-9 ofFIGURE 6 illustrating the loader attachment and how the rings areinitially compressed and fed into a tapered portion of the fixtureadapted to close the ring gap.

Referring now to the drawings and particularly FIG- URE 1, the specialfixture is shown to include a base plate member indicated by a numeral2. Mounted on the base 2 by brackets 4 is the magazine or loading barassembly indicated generally by the numeral 6.

Referring particularly to FIGURES 2, 6, 7, 8 and 9, it will be observedthat this magazine includes an elongated cylindrical member 8 havingupper and lower diametrically opposed slots 1t and 12, respectively. Thecylindrical member 8 is provided with a guide bar 14 (see FIGURES 2 and8) which is secured thereto by welding and which in turn is fixed to thebrackets 4 by the studs 16. The guide bar 14- is dimensioned so that therings 18 mounted on magazine 6 will slide therealong and the gapsthereof will just receive the bar.

To assure that the rings 18 will move into the loader attachment, whichis indicated generally by a numeral 20, a pair of keys 22 have beenprovided which engage the last or outermost ring. These keys are movableradially in a plate assembly 24 (see FIGURE 8) so that they enter slots18 and 12. Their radial movement is controlled by a rod and handleassembly 26 extending axially through the cylindrical member 8 to theplate assembly 24 which has on an end thereof a pair of cam pieces 28 toengage the innermost ends of the keys 22,. The keys 22 may be movedradially outwardly by rotation of the rod 26 and operating handle 30' onthe opposite end thereof. It will be noted particularly in FIGURE 7 thatthe keys or fingers 22 are normally biased radially toward the center ofplate assembly 24 by a small helical spring 32 connected between pins 34fixed to each key 22 and riding in slots 36 in the plate assembly 24. Itwill be appreciated that it is necessary to be able to retract the keys22 in order to load the rings 18 on the magazine.

When the keys 222 are in their outermost radial position so that theyengage the last or outermost ring on the magazine, the rings are allbiased toward the loader attachment indicated generally by the numeral20. This bias is achieved by means of a helical coil spring 38 which isfastened between the plate assembly 24 and an anchoring plate 44 fixedin the end of the cylindrical member 8 at its end adjacent the loaderattachment 2%. To further assure that the rings '18 are received in theloader attachment 2.0; a pair of permanent magnets 42 have been mountedin the outermost plate 44 of loader attachment 20.

Referring now particularly to FIGURE 9', it will be observed that theloader attachment indicated generally by the numeral 20' is made up of aplurality of flat plates which provide a fiat tapered clearance 46'therebetween for the reception of a single ring. Also located in thisflat clearance is a formed plate pusher 48 which is energized oractuated in a lineal direction by suitable hydraulicor pneumatic meansnot shown. With a ring received in the flat clearance 4-6, energizationof the plate pusher 48 will move the ringin the area 46 in the directionof the taper thereof thereby compressing the ring and tending to closeits gap. As the piston ring is forced ahead by the plate pusher 4 8 itenters through a slot 50 in the cylindrical carrier of the fixtureindicated generally by a numeral 52. The carrier 52 as best seen in FIG-URES 2, 3, 4 and 5 is mounted. for [reciprocal movement in a bore 5'4which is formed in cylindrical supporting assembly 56 mounted on plate2.

Movement of carrier 52 backward and forward is accomplished byenergization of a hydraulic servo 53 and a suitable driving linkage 60Carrier 52 is provided with a bore 62 which, it will be noted, has asmall axially extending taper 64 immediately behind the slot 5t)therein. Immediately forward of the slot 50 is a ring 66 fixed to theend of the carrier which forms an abutting shoulder 68 to prevent thering 18 from falling out of the forward end of the carrier.

Assuming now that the carrier is moved forward by energization of theservo 58, the ring 66 will enter an annular opening or recess 70 adaptedto receive it. The opening 70 is provided in a radial flange 72 providedon Patented Sept. 24, lacs.

It will be noted that the carrier 52 has located in the center thereof alive center or tailstock indicated generally by a numeral 76. Thistailstock 76may be independently energized by servo 77 so that it alsocanmove forward. As it does so, its face plate 78 engages the ring andalso clamps it securely against the face plate 74 of the grindingfixture. Once the ring is securely clamped between the plates 74 and 78,the carrier '52 may now be retracted (see FIGURE 5) leaving the pistonringouter face open for grinding by the abrading tool of the grindershown in phantom and indicated by a numeral 80.

It will be observed that the live center or tailstock 76 includestapered roller bearing assemblies 82 adapted to take both thrust andradial loads in order to allow the ring 18 clamped between plates '74and 78 to rotate with these plates as the face plate 74 of the grindingfixture is rotatably driven by a suitable power means such as. anelectrical motor. When the grinding operation has been completed thetailstock is moved away from ring 18 to the position shown in FIGURE 3by energization of servo 77. The ring 18 will then drop away from faceplate 74 and the fixture is ready to receive the next ring 18 forgrinding.

From the foregoing it may now be appreciated that a unique grindingfixture has been provided and a method offered whereby piston rings maybe fed one at a time, compressed and clamped in proper position toenable them to be individually ground.

I claim:

1. A ring grinding fixture comprising means for radially compressing thering including means, forming a flat elongated substantially rectangularclearance tapered at one end along the plane of said clearance andhaving an aperture therein for the reception of a split piston ring inthe plane of said clearance, a ring pusher movable back and forth in theplane of said clearance adapted to engage one side of a split ringtherein and push it in the direction of said taper, means for clampingthe ring when compressed, means for turning said. clamping meanswith thering clamped thereby and means to release said clamping means.

2. A ring grinding fixture comprising first means for radiallycompressing the ring including means forming a flat elongatedsubstantially rectangular clearance tapered at one end along the planeof said clearance and having an aperture therein for the reception of asplit piston ring in the plane of said clearance, a ring pusher movableback and forth in the plane of said clearance adapted to engage one sideof a split ring therein and push it in the direction of said taper, arotatable face plate, second means to move said compressed ring againstsaid face plate, third means to hold said ring against said face platefor rotation therewith, means to withdraw said second means, and meansto release said third means.

3. For use in combination with a ring grinding fixture, means toindividually radially compress the rings to be ground comprising meansforming a flat elongated substantially rectangular clearance tapered atone end along the plane thereof and having an aperture therein for thereception of a split piston ring in the plane of said clearance, a ringpusher movable back and forth in the plane of said clearance adapted toengage one side of a split ring therein and push it in the direction ofsaid taper.

4. The combination claimed in claim 3 which further includes a magnetmounted on said means forming said clearance to attract a ring throughsaid aperture.

5. The combination claimed in claim 3 which further incudes a ringmagazine extending transversely from the means forming said clearance inline with said aperture and means on said magazine tending to force anyrings thereon toward said aperture.

References Cited in the file of this patent UNITED STATESPATENTS1,190,553 Johnson July 11, 1916 1,414,190 Koehler Apr. 25, 19221,454,350 Teetor May 8, 1923 1,494,913 Hughes May 20, 1924 1,654,736Kistner Jan. 3, 1928 1,778,899. Kottusch Oct. 21, 1930 1,885,848 MarchNov. 1, 1932 2,140,682 Strauss Dec. 20, 1938 2,510,206 Barkan et al June6, 1950 2,697,870 Zucker Dec. 28, 1954 2,749,672 Haldeman June 12, 19562,764,850 Busey Oct. 2, 1956 2,785,512 Hutto Mar. 19, 1957 2,792,625Hoffman May 21, 1957 2,835,085 Manting May 20, 1958 2,840,892 ErdmannJuly 1, 1958 2,856,678 Johnson Oct. 21, 1958' 2,924,917 Rice Feb. 16,1960 FOREIGN PATENTS 667,935 Great Britain Mar. 12, 1952

1. A RING GRINDING FIXTURE COMPRISING MEANS FOR RADIALLY COMPRESSING THERING INCLUDING MEANS FORMING A FLAT ELONGATED SUBSTANTIALLY RECTANGULARCLEARANCE TAPERED AT ONE END ALONG THE PLANE OF SAID CLEARANCE ANDHAVING AN APERTURE THEREIN FOR THE RECEPTION OF A SPLIT PISTON RING INTHE PLANE OF SAID CLEARANCE, A RING PUSHER MOVABLE BACK AND FORTH IN THEPLANE OF SAID CLEARANCE ADAPTED TO ENGAGE ONE SIDE OF A SPLIT RINGTHEREIN AND PUSH IT IN THE DIRECTION OF SAID TAPER, MEANS FOR CLAMPINGTHE RING WHEN COMPRESSED, MEANS FOR TURNING SAID CLAMPING MEANS WITH THERING CLAMPED THEREBY AND MEANS TO RELEASE SAID CLAMPING MEANS.